594 research outputs found

    Communicating with International Students: How do their social networks impact on where they go to for information?

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    Nearly all institutions that attract international students provide crucial information — particularly in relation to non-academic issues (e.g. access health services, food, accommodation, and leisure activities) — to these students while they are in Australia. However, this information is not well accessed by the students because of the lack of understanding on how international students search, access, use, rely on or share information. This paper therefore investigates how international students access information related to non-academic issues and provides insights into ways institutions can engage with their international students in the online environment. Through analysing interview data from a series of 8 focus groups, this early research shows that international students display different information seeking behaviour depending on the social networks they belong to while in Australia. By mapping the social networks of international students, this paper suggests some practical implications to effectively provide information to international students

    Investigation of Memory Related Cortical Thalamic Circuitry in the Human Brain

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    This dissertation examined the role of medial prefrontal cortex (mPFC) and the hippocampus (HC) in episodic memory, and provides a novel approach to identify the midline thalamus mediating mPFC-HC interactions in humans. The mPFC and HC are critical to the temporal organization of episodic memory, and these interactions are disrupted in several mental health and neurological disorders. In the first study, I provide evidence that the mPFC is involved in ordinal retrieval, and the HC is active in temporal context retrieval in remembering the order of when events happen. In the second study, I focus on the anatomical basis of the mPFC-HC interactions which is reliant on the midline thalamus. I review in detail the anatomy of the midline thalamus both in location, and connectivity profile with the rest of the brain comparing the extensive anatomical evidence in rodents with the available evidence in monkeys and humans. This section also elaborates on the role of the midline thalamus in memory, stress regulation, wakefulness, and feeding behavior, and how pathological markers along the midline thalamus are a vanguard of several neurological disorders including Alzheimer’s Disease, schizophrenia, depression, and drug addiction. Lastly, I devised a new approach to identify the midline thalamus in humans in vivo using diffusion weighted imaging, capitalizing on known fiber connections gleaned from non-human animals, focusing on connections between the midline thalamus and the mPFC, medial temporal lobe and the nucleus accumbens. The success of this approach is promising for translational imaging. Overall, this dissertation provides new evidence on 1) complementary functional roles of the mPFC and HC in sequence memory, 2) a cross-species anatomical framework for understanding the midline thalamus in humans and neurological disorders, and 3) a new method for non-invasive identification of the midline thalamus in humans in vivo. Thus, this dissertation provides a new fundamental understanding of mPFC-midline thalamic-HC circuit in humans and tools for its non-invasive study in human disease

    Effects of the Invasive Freshwater Mussel Limnoperna fortunei on Sediment Properties and Accumulation Rates

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    Since its introduction into South America around 1990, the freshwater bivalve Limnoperna fortunei (the golden mussel) has spread rapidly and is now a dominant component of the benthic and periphytic fauna in many rivers, lakes, and reservoirs. Sizable impacts of this nonindigenous species on nutrient recycling, plankton abundance and composition, and trophic relationships with fishes have been reported, but its effects on the sediments have received little attention. In this work, we use eighteen 20-L flow-through experimental units with and without mussels where changes in the mass and characteristics of the sediments accumulated throughout a yearly cycle in monthly, biannual, and annual intervals are analyzed. Experimental units with mussels yielded almost 2 times more sediments than units without mussels and contained significantly higher loads of organic matter and total N. Total P was not affected by the presence of mussels. Sediments accumulated in the biannual and annual experimental units agreed well with the yields of the monthly units, but the vertical stratification of organic matter, N, and P was unpatterned. Seasonal changes in the volume of total sediments, biodeposits, and their organic matter and N contents were positively associated with ambient water temperature and with intermediate (~150–250 NTU, nephelometric turbidity units) turbidity. Our results suggest that ecosystem-wide modifications in the living conditions of the benthic epifaunal and infaunal organisms in waterbodies invaded by the mussel are likely significant, although variable locally, regionally, and across taxa.Fil: Tokumon, Romina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Boltovskoy, Demetrio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Cataldo, Daniel Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

    Medial prefrontal cortex and hippocampal activity differentially contribute to ordinal and temporal context retrieval during sequence memory

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    Remembering sequences of events defines episodic memory, but retrieval can be driven by both ordinality and temporal contexts. Whether these modes of retrieval operate at the same time or not remains unclear. Theoretically, medial prefrontal cortex (mPFC) confers ordinality, while the hippocampus (HC) associates events in gradually changing temporal contexts. Here, we looked for evidence of each with BOLD fMRI in a sequence task that taxes both retrieval modes. To test ordinal modes, items were transferred between sequences but retained their position (e.g., AB3). Ordinal modes activated mPFC, but not HC. To test temporal contexts, we examined items that skipped ahead across lag distances (e.g., ABD). HC, but not mPFC, tracked temporal contexts. There was a mPFC and HC by retrieval mode interaction. These current results suggest that the mPFC and HC are concurrently engaged in different retrieval modes in support of remembering when an event occurred
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